The proposed investigation is designed to characterize hazards that may befall both pregnant and non-pregnant females engaged in occupations in Shich pesticide exposure is a distinct possibility. This study will examine the effects of four commonly used pesticides (DDT, diazinon, carbaryl and malathion) on embryonic development of the gonads in both avian (chick) and mammalian (mouse) species and the effects of pre- and postnatal pesticide exposure on basic reproductive processes in the adult female mouse. Parameters used for assessment of alterations in reproductive functions include ovulatory response to exogenous gonadotropins, oocyte maturation and steroidogenesis within the ovary. Data has been obtained which clearly demonstrates that even with a uniform method of injection (into the yolk sac) into the chick embryo, the toxic effects of pesticides can be modified by the vehicle in which the pesticide is presented to the embryo. Experiments involving exposure of chick embryos to carbaryl demonstrate that long-term exposure (12 days) is necessary for external developmental anomalies to occur. Embryonic abnormalities such as subcutaneous edema and defects in lower limb development were common in carbaryl-exposed embryos.